Method and Network Node for Obtaining Target Transmission Path

ABSTRACT

A method and network node for obtaining a target transmission path, where the method includes obtaining, by a first network node in a network domain, topology information of a plurality of network nodes on each path between an ingress node and an egress node that are in the network domain, obtaining, by the first network node, a transmission delay of each path according to the topology information, where the transmission delay of each path includes a sum of physical link delays between all network nodes on each path and node residence times of all the network nodes on each path, and determining, by the first network node, the target transmission path according to the transmission delay of each path.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Patent ApplicationNo. PCT/CN2016/104055 filed on Oct. 31, 2016, which claims priority toChinese Patent Application No. 201510796056.7 filed on Nov. 18, 2015.The disclosures of the aforementioned applications are herebyincorporated by reference in their entireties.

TECHNICAL FIELD

The present disclosure relates to the communications field, and inparticular, to a method and network node for obtaining a targettransmission path.

BACKGROUND

An Internet Protocol (IP) or Multiprotocol Label Switching (MPLS)network generally needs to support low-delay traffic, for example, alow-delay requirement on mobile carrier traffic in a fourth-generation(4G) or later-generation network, for example, a requirement of an X2interface for a delay less than or equal to 10 milliseconds (ms)(defined in third Generation Partnership Project (3GPP)). Although atraffic bandwidth of the X2 interface accounts for only 2% to 5% of atotal mobile traffic bandwidth, the delay requirement of the X2interface is high. For another example, transmission of monitoringinformation and a command in a smart grid requires a constantly stablebut not high bandwidth, and also requires a low delay and highreliability in the network. Otherwise, a grid fault may occur. Foranother example, a network delay of a multichannel audio/video in acommercial show/sports competition site needs to be less than or equalto 15 ms.

A quality of service (QoS) technology such as a differentiated service(DiffServ) is applied to a current IP or MPLS network, and traffic withdifferent QoS requirements can be transmitted on a same path ordifferent paths according to the different QoS requirements. However,the current IP or MPLS network is essentially a packet multiplexingnetwork, and therefore, queuing and even congestion of high-prioritypackets in a queue are inevitable. Consequently, a delay may exceed athreshold in the network, and in a worst case, a packet loss occurs.Moreover, confining an end-to-end delay of traffic of a low-delayservice within a specific threshold in an actual forwarding processcannot be ensured.

The Internet Engineering Task Force (IETF) already considers to take alink delay as a routing measure for the Intermediate System toIntermediate System (IS-IS) protocol and the Open Shortest Path First(OSPF) routing protocol. However, no specific link delay measurementmechanism is provided by either of the protocols, causing a disadvantagethat the protocols are mainly applicable to a network environment inwhich a physical link transmission delay accounts for a majorproportion, and are not sufficiently applicable to a metropolitan areanetwork or a network with smaller coverage.

In the industry, there are already delay measurement technologies formeasuring a 1-way delay or 2-way delay of MPLS transport profile(MPLS-TP) operation, administration, and maintenance (OAM). However, aconfiguration of an OAM mechanism is fixed and based on a maintenanceentity group (MEG) end point (MEP). The OAM mechanism can neither beassociated with a specific queue, nor measure network-wide delay pathsin a distributed manner. Delay measurement of the OAM mechanism hasinherent defects. For example, a service-layer OAM packet and a servicepacket enter a same priority queue after same QoS processing, andconsequently, an instantaneous queue length affects delay measurement, alink-layer OAM packet cannot measure a node residence time. In addition,a main purpose of a service-layer OAM packet is to measure an actualdelay of a service, and a channel associated with service traffic isused. This is congenitally deficient in transcendentally obtaining apath.

SUMMARY

The present disclosure provides a method for obtaining a targettransmission path and a network node in order to enable the targettransmission path to meet a delay requirement of a service.

According to a first aspect, a method for obtaining a targettransmission path is provided. The method is applied to a networkdomain, and the method includes obtaining, by a first network node inthe network domain, topology information of a plurality of network nodesincluded by each path between an ingress node and an egress node thatare in the network domain, where the topology information includes aphysical link delay between two adjacent network nodes in the pluralityof network nodes and a node residence time of each of the plurality ofnetwork nodes, obtaining, by the first network node, a transmissiondelay of each path between the ingress node and the egress nodeaccording to the topology information, where the transmission delay ofeach path includes a sum of the physical link delay between the twoadjacent network nodes on each path and node residence times of theplurality of network nodes on each path, and determining, by the firstnetwork node, a target transmission path between the ingress node andthe egress node according to the transmission delay of each path.

According to the method for obtaining a target transmission path in thisembodiment of the present disclosure, each network node in the networkdomain measures a physical link delay between each network node and aneighboring node and a node residence time. Each network node may obtaina physical link delay between other network nodes and node residencetimes using topology information in order to determine a targettransmission path that is in the network domain and that meets a delayrequirement, and transmit a low-delay service packet using the targettransmission path. Therefore, this can ensure that transmission of alow-delay service in a network meets the delay requirement, and aplurality of low-delay paths between the ingress node and the egressnode in the network can be fully utilized, thereby improvingtransmission reliability of the low-delay service.

With reference to the first aspect, in an implementation of the firstaspect, the method further includes obtaining, by the first networknode, topology information of all network nodes in the network domain,where the topology information of all the network nodes includes aphysical link delay between two adjacent network nodes in the networkdomain and a node residence time of each network node in the networkdomain, obtaining, by the first network node, the transmission delay ofeach path between the ingress node and the egress node that are in thenetwork domain according to the topology information, where thetransmission delay of each path includes a sum of the physical linkdelay between the two adjacent network nodes on each path and noderesidence times of all the network nodes on each path, and determining,by the first network node, the target transmission path between theingress node and the egress node according to the transmission delay ofeach path.

With reference to the first aspect and the foregoing implementation, inanother implementation of the first aspect, the topology informationincludes first topology information, and obtaining, by a first networknode in the network domain, topology information of a plurality ofnetwork nodes included by each path between an ingress node and anegress node that are in the network domain includes obtaining, by thefirst network node, a first physical link delay in the first topologyinformation, where the first physical link delay is a link delay betweenthe first network node and an adjacent first neighboring node, andobtaining, by the first network node, a node residence time that is ofthe first network node and that is in the first topology information.

With reference to the first aspect and the foregoing implementations, inanother implementation of the first aspect, the topology informationincludes second topology information, and obtaining, by a first networknode in the network domain, topology information of a plurality ofnetwork nodes included by each path between an ingress node and anegress node that are in the network domain includes receiving, by thefirst network node, the second topology information sent by a secondnetwork node in the plurality of network nodes, where the secondtopology information includes a second physical link delay between thesecond network node and a second neighboring node in the plurality ofnetwork nodes and a node residence time of the second network node, andthe second neighboring node is a neighboring node of the second networknode.

With reference to the first aspect and the foregoing implementations, inanother implementation of the first aspect, the first network node sendsthe first topology information to the second network node such that thesecond network node determines the target transmission path according tothe first topology information.

With reference to the first aspect and the foregoing implementations, inanother implementation of the first aspect, obtaining, by the firstnetwork node, a node residence time that is of the first network nodeand that is in the first topology information includes obtaining, by thefirst network node, load of the first network node, and obtaining, bythe first network node, the node residence time of the first networknode according to the load and a mapping table, where the mapping tableincludes a correspondence between the load and the node residence timethat are of the first network node.

With reference to the first aspect and the foregoing implementations, inanother implementation of the first aspect, obtaining, by the firstnetwork node, a first physical link delay in the first topologyinformation includes receiving, by the first network node, a delaymeasurement packet directly sent by the first neighboring node, wherethe delay measurement packet includes a sending time stamp of sendingthe delay measurement packet by the first neighboring node, andobtaining, by the first network node, the first physical link delaybetween the first network node and the first neighboring node accordingto a receiving time stamp of receiving the delay measurement packet andthe sending time stamp in the delay measurement packet.

With reference to the first aspect and the foregoing implementations, inanother implementation of the first aspect, obtaining, by the firstnetwork node, a first physical link delay in the first topologyinformation includes receiving, by the first network node, a pluralityof delay measurement packets directly sent by the first neighboringnode, where each of the plurality of delay measurement packets includesa sending time stamp of sending each delay measurement packet by thefirst neighboring node, obtaining, by the first network node, aplurality of physical link delays between the first network node and thefirst neighboring node according to a receiving time stamp of receivingeach delay measurement packet and the sending time stamp in each delaymeasurement packet, and determining, by the first network node, thefirst physical link delay by collecting statistics on the plurality ofphysical link delays.

With reference to the first aspect and the foregoing implementations, inanother implementation of the first aspect, the target transmission pathis used to transmit a low-delay service packet in a low-delay packetqueue, and a transmission delay of the target transmission path meets adelay requirement of the low-delay service packet.

With reference to the first aspect and the foregoing implementations, inanother implementation of the first aspect, determining, by the firstnetwork node, a target transmission path between the ingress node andthe exist node according to the transmission delay of each path includesdetermining, by the first network node as the target transmission path,a path that is in all paths between the ingress node and the egress nodeand that is corresponding to a minimum transmission delay, where thelow-delay service packet is transmitted using the target transmissionpath, to ensure that transmission of the low-delay service in thenetwork meets the delay requirement.

With reference to the first aspect and the foregoing implementations, inanother implementation of the first aspect, determining, by the firstnetwork node, a target transmission path between the ingress node andthe exist node according to the transmission delay of each path includesdetermining, by the first network node as the target transmission path,one path in a plurality of paths that are in all paths between theingress node and the egress node and whose transmission delays meet thedelay requirement.

With reference to the first aspect and the foregoing implementations, inanother implementation of the first aspect, determining, by the firstnetwork node, a target transmission path between the ingress node andthe exist node according to the transmission delay of each path includesdetermining, by the first network node as the target transmission path,at least two paths in a plurality of paths that are in all paths betweenthe ingress node and the egress node and whose transmission delays meetthe delay requirement of the low-delay service packet, where each of theat least two paths separately transmits each low-delay service packet inthe low-delay packet queue, thereby improving the transmissionreliability of the low-delay service.

With reference to the first aspect and the foregoing implementations, inanother implementation of the first aspect, determining, by the firstnetwork node, a target transmission path between the ingress node andthe exist node according to the transmission delay of each path includesdetermining, by the first network node as the target transmission path,at least two paths in a plurality of paths that are in all paths betweenthe ingress node and the egress node and whose transmission delays meetthe delay requirement of the low-delay service packet, where the atleast two paths transmit the low-delay service packet in the low-delaypacket queue in a load sharing manner such that the plurality oflow-delay paths between the ingress node and the egress node in thenetwork can be fully utilized, thereby improving the transmissionreliability of the low-delay service.

With reference to the first aspect and the foregoing implementations, inanother implementation of the first aspect, the first network node isthe ingress node or the egress node.

With reference to the first aspect and the foregoing implementations, inanother implementation of the first aspect, the second network node isthe ingress node or the egress node.

According to a second aspect, a network node for obtaining a targettransmission path is provided, where the network node is a first networknode in a network domain, and the first network node includes a firstobtaining unit configured to obtain topology information of a pluralityof network nodes included by each path between an ingress node and anegress node that are in the network domain, where the topologyinformation includes a physical link delay between two adjacent networknodes in the plurality of network nodes and a node residence time ofeach of the plurality of network nodes, and a second obtaining unitconfigured to obtain a transmission delay of each path between theingress node and the egress node according to the topology information,where the transmission delay of each path includes a sum of the physicallink delay between the two adjacent network nodes on each path and noderesidence times of the plurality of network nodes on each path, and adetermining unit configured to determine a target transmission pathbetween the ingress node and the egress node according to thetransmission delay of each path.

In a first possible implementation of the second aspect, the topologyinformation includes first topology information, and the first obtainingunit is further configured to obtain a first physical link delay in thefirst topology information, where the first physical link delay is alink delay between the first network node and an adjacent firstneighboring node, and the first neighboring node and the first networknode belong to the plurality of network nodes, and obtain a noderesidence time that is of the first network node and that is in thefirst topology information.

With reference to the second aspect or the first possible implementationof the second aspect, in a second possible implementation of the secondaspect, the topology information includes second topology information,and the first obtaining unit is further configured to receive the secondtopology information sent by a second network node in the plurality ofnetwork nodes, where the second topology information includes a secondphysical link delay between the second network node and a secondneighboring node in the plurality of network nodes and a node residencetime of the second network node, and the second neighboring node is aneighboring node of the second network node.

With reference to the first possible implementation of the secondaspect, in a third possible implementation of the second aspect, thefirst obtaining unit is further configured to obtain load of the firstnetwork node, and obtain the node residence time of the first networknode according to the load and a mapping table, where the mapping tableincludes a correspondence between the load and the node residence timethat are of the first network node.

With reference to the first possible implementation of the second aspector the third possible implementation of the second aspect, in a fourthpossible implementation of the second aspect, the first obtaining unitis further configured to receive a delay measurement packet directlysent by the first neighboring node, where the delay measurement packetincludes a sending time stamp of sending the delay measurement packet bythe first neighboring node, and obtain the first physical link delayaccording to a receiving time stamp of receiving the delay measurementpacket and the sending time stamp in the delay measurement packet.

With reference to the first possible implementation of the second aspector the third possible implementation of the second aspect, in a fifthpossible implementation of the second aspect, the first obtaining unitis further configured to receive a plurality of delay measurementpackets directly sent by the first neighboring node, where each of theplurality of delay measurement packets includes a sending time stamp ofsending each delay measurement packet by the first neighboring node,obtain a plurality of physical link delays between the first networknode and the first neighboring node according to a receiving time stampof receiving each delay measurement packet and the sending time stamp ineach delay measurement packet, and determine the first physical linkdelay by collecting statistics on the plurality of physical link delays.

With reference to the second aspect or any possible implementation ofthe second aspect, in a sixth possible implementation of the secondaspect, the target transmission path is used to transmit a low-delayservice packet in a low-delay packet queue, and a transmission delay ofthe target transmission path meets a delay requirement of the low-delayservice packet.

With reference to the second aspect or any possible implementation ofthe second aspect, in a seventh possible implementation of the secondaspect, the determining unit is further configured to determine, as thetarget transmission path, at least two paths in a plurality of pathsthat are in all paths between the ingress node and the egress node andwhose transmission delays meet the delay requirement of the low-delayservice packet, where the at least two paths transmit the low-delayservice packet in the low-delay packet queue in a load sharing manner.

The network node for obtaining a target transmission path provided inthe second aspect may be configured to execute the method in the firstaspect or any possible implementation of the first aspect. Further, thenetwork node includes a unit configured to execute the method in thefirst aspect or any possible implementation of the first aspect.

According to a third aspect, a network node for obtaining a targettransmission path is provided, including a memory and a processor. Thememory is configured to store an instruction, and the processor isconfigured to execute the instruction stored in the memory. When theprocessor executes the instruction stored in the memory, the processorexecutes the method according to the first aspect or any possibleimplementation of the first aspect.

According to a fourth aspect, a computer readable medium is provided,and is configured to store a computer program. The computer programincludes an instruction for executing the method according to the firstaspect or any possible implementation of the first aspect.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic diagram of a network domain according to anembodiment of the present disclosure;

FIG. 2 is a flowchart of a method for obtaining a target transmissionpath according to an embodiment of the present disclosure;

FIG. 3 is a schematic diagram of forwarding and scheduling of a delaymeasurement packet according to an embodiment of the present disclosure;

FIG. 4 is a schematic diagram of a network node for obtaining a targettransmission path according to an embodiment of the present disclosure;and

FIG. 5 is another schematic diagram of a network node for obtaining atarget transmission path according to an embodiment of the presentdisclosure.

DESCRIPTION OF EMBODIMENTS

The following clearly describes the technical solutions in theembodiments of the present disclosure with reference to the accompanyingdrawings in the embodiments of the present disclosure. The describedembodiments are a part rather than all of the embodiments of the presentdisclosure.

An IP or MPLS network may include a plurality of network nodes. As shownin FIG. 1, FIG. 1 may be considered as a partial schematic diagram of ametropolitan area network. A network domain herein may be a whole set ofnetwork nodes that are interconnected in the physical topology and thatrun a same routing protocol. In addition, the network domain can supporta routing implementation method described in the embodiments of thepresent disclosure. In the network domain shown in FIG. 1, a pluralityof intermediate network nodes, that is, a network node 1 to a networknode 7 (designated as 1, 2, 3, 4, 5, 6 and 7 in FIG. 1), are includedbetween a PE1 and a PE2 that are between a source (SRC) and adestination (DST). These network nodes form a plurality of transmissionpaths between the PE1 and the PE2. The PE1 and the PE2 are edge nodes,that is, provider edge (PE) devices.

In the metropolitan area network shown in FIG. 1, when the edge nodesPE1 and PE2 and each of the intermediate network nodes forward packets,many queues are configured to cache received packets. For example,common queues include a priority queue, a fair queue, a weighted fairqueue, and the like. Each network node may arrange received packets intodifferent queues according to different priorities of the receivedpackets. Further, a total length and a specific scheduling mechanism ofa packet queue are related to an actual configuration for deviceimplementation and running, and this is not limited in the presentdisclosure.

This embodiment of the present disclosure mainly targets at a low-delayservice, and a low-delay service packet has a requirement on atransmission delay. When obtaining a low-delay service packet, a networknode usually arranges the low-delay service packet into a high-prioritypacket queue. A transmission delay of the packet queue in a transmissionpath from an ingress node to an egress node is less than or equal to apreset value. For example, the transmission path from the ingress nodeto the egress node may be a path from the PE1 to the PE2.

FIG. 2 shows a schematic flowchart of a method 100 for obtaining atarget transmission path according to an embodiment of the presentdisclosure. The method 100 may be executed by any network node in aplurality of nodes included in a network domain. The any node herein isreferred to as a first network node. For example, the first network nodemay be any intermediate network node in FIG. 1, that is, any node in thenetwork node 1 to the network node 7, or the first network node may bethe edge node PE1 or PE2, and this is not limited in the presentdisclosure. As shown in FIG. 2, the method 100 includes the followingsteps.

Step S110. The first network node in the network domain obtains topologyinformation of a plurality of network nodes included by each pathbetween an ingress node and an egress node that are in the networkdomain, where the topology information includes a physical link delaybetween two adjacent network nodes in the plurality of network nodes anda node residence time of each of the plurality of network nodes.

Step S120. The first network node obtains a transmission delay of eachpath between the ingress node and the egress node according to thetopology information, where the transmission delay of each path includesa sum of the physical link delay between the two adjacent network nodeson each path and node residence times of the plurality of network nodeson each path.

Step S130. The first network node determines a target transmission pathbetween the ingress node and the egress node according to thetransmission delay of each path.

Further, it is assumed that each network node in the network domain cansupport a protocol similar to a high precision clock synchronizationprotocol, and can maintain high precision clock synchronization in anetwork for a long period. The first network node is used as an exampleof each of the plurality of network nodes in the network domain. Thefirst network node may measure a physical link delay between the firstnetwork node and a neighboring node, and may further measure a noderesidence time of the first network node. After obtaining a physicallink delay and a node residence time through measurement, each networknode may send the physical link delay between each network node and aneighboring node and the node residence time of each network node toeach network node in the network domain using topology information. Forexample, the first network node may receive a physical link delay and anode residence time of each network node that are sent by anothernetwork node, and may further send the physical link delay between thefirst network node and the neighboring node and the node residence timeof the first network node to another node. In this way, the firstnetwork node may determine, according to the physical link delay and thenode residence time of each node in the network domain, the targettransmission path between the ingress node and the egress node that arein the network domain. The target transmission path meets a delayrequirement and may be used to transmit a low-delay service packet.

Therefore, according to the method for obtaining a target transmissionpath in this embodiment of the present disclosure, each network node inthe network domain measures the physical link delay between each networknode and a neighboring node and the node residence time. Each networknode may obtain a physical link delay between other nodes and noderesidence times of the other nodes using topology information in orderto determine the target transmission path that is in the network domainand that meets the delay requirement, and transmit a low-delay servicepacket using the target transmission path. Therefore, this can ensurethat transmission of a low-delay service in the network meets the delayrequirement, and a plurality of low-delay paths between the ingress nodeand the egress node in the network can be fully utilized, therebyimproving transmission reliability of the low-delay service.

In step S110, the first network node in the network domain may obtainthe topology information of the plurality of network nodes included byeach path between the ingress node and the egress node that are in thenetwork domain. The topology information includes the physical linkdelay between the two adjacent network nodes in the plurality of networknodes and the node residence time of each of the plurality of networknodes. The first network node is any network node in the network domain,each path between the ingress node and the egress node may include aplurality of network nodes, and the plurality of network nodes on eachpath include the ingress node and the egress node. Optionally, the firstnetwork node may further obtain topology information of each of othernetwork nodes included in the network domain. The topology informationincludes a physical link delay between each network node and a neighbornetwork node and a node residence time of each network node.

Further, when the first network node is a network node on any pathbetween the ingress node and the egress node, the topology informationobtained by the first network node may include first topologyinformation and may further include second topology information. Thefirst topology information is obtained by the first network node, andthe first topology information includes a first physical link delaybetween the first network node and a first neighboring node and the noderesidence time of the first network node. The first neighboring node isa neighboring node of the first network node and is also on the pathbetween the ingress node and the egress node. The second topologyinformation is sent by a second network node and received by the firstnetwork node. The second network node is another network node in thenetwork domain except the first network node. The second network node isalso on the path between the ingress node and the egress node. Thesecond topology information includes a second physical link delaybetween the second network node and a second neighboring node and a noderesidence time of the second network node. The second neighboring nodeis a neighboring node of the second network node and is also on the pathbetween the ingress node and the egress node.

Optionally, when the first network node is neither the ingress node northe egress node, the first network node may not obtain the firsttopology information of the first network node but obtain only topologyinformation of network nodes included by each path between the ingressnode and the egress node, that is, the second topology information ofthe second network node on the path between the ingress node and theegress node.

Optionally, when the first network node is neither the ingress node northe egress node, the first network node may also obtain the firsttopology information of the first network node, may further obtaintopology information of network nodes included by each path between theingress node and the egress node, and may further obtain topologyinformation of another network node not on the path between the ingressnode and the egress node, that is, the first network node may obtaintopology information of each network node in the network domain. In thisway, regardless of any change of the ingress node and the egress node,the first network node may obtain the topology information of thenetwork nodes included by each path between the ingress node and theegress node in order to avoid repeated topology information measurementand obtaining. However, this is not limited in this embodiment of thepresent disclosure.

In this embodiment of the present disclosure, an example in which thefirst network node obtains the first topology information is used fordescription. The first network node is any network node in the networkdomain. The first network node may perform measurement on a physicallink delay by sending a delay measurement packet, that is, the firstnetwork node may obtain the first physical link delay between the firstnetwork node and the neighboring node using the delay measurementpacket. Further, the first network node receives a delay measurementpacket sent by the first neighboring node. The first neighboring node isadjacent to the first network node, and the delay measurement packetincludes a sending time stamp of sending the delay measurement packet bythe first neighboring node. Then, the first network node may obtain thephysical link delay between the first network node and the firstneighboring node according to a receiving time stamp of receiving thedelay measurement packet and the sending time stamp in the delaymeasurement packet. The delay measurement packet is directly sent by thefirst neighboring node to the first network node.

Optionally, in an embodiment, for example, as shown in FIG. 1, if thefirst network node is the node 4 in FIG. 1 and the first neighboringnode is the node 6 in FIG. 1, that is, a physical link delay between thenode 6 and the node 4 is to be measured, the node 6 sends a delaymeasurement packet to the node 4, and the delay measurement packetincludes a sending time stamp t1 of sending the delay measurement packetby the node 6, after receiving the delay measurement packet, the node 4obtains a receiving time stamp t2, and may obtain the physical linkdelay between the node 6 and the node 4 according to the receiving timestamp t2 and the sending time stamp t1.

Optionally, for a physical link delay between any two adjacent networknodes, for example, the delay between the first network node and thefirst neighboring node, a delay from the first network node to the firstneighboring node may be seen as equal to a delay from the firstneighboring node to the first network node, that is, the delay from thefirst network node to the first neighboring node is equal to the delayfrom the first neighboring node to the first network node. Optionally,the delay from the first network node to the first neighboring node maybe seen as unequal to the delay from the first neighboring node to thefirst network node, and the delay from the first network node to thefirst neighboring node and the delay from the first neighboring node tothe first network node may be separately measured. This is not limitedin the present disclosure.

In this embodiment of the present disclosure, a specific queuing delayof a single data packet in a queue is related to an instantaneous statusof the current queue of the data packet. Measuring such a delay orchanging a packet scheduling mechanism according to such a delay is oflittle significance. Therefore, a delay measurement packet may beinserted into the head of a low-delay service queue in order to avoidimpact caused by the queue itself, and a specific queuing delay in thesame low-delay service queue may be not considered. Optionally, as shownin FIG. 3, generally, a low-delay packet queue occupied by a low-delayservice packet may be a high-priority queue, and the delay measurementpacket may be located in the head of the low-delay packet queue, and thelow-delay packet queue is followed by a queue of another priority. Thisis not limited in the present disclosure.

In this embodiment of the present disclosure, the physical link delaybetween any two adjacent network nodes may be measured a plurality oftimes by sending a plurality of delay measurement packets, andstatistics on results of the plurality of times of measurement may becollected, for example, an average value may be obtained, an expectationvalue may be calculated, a maximum value may be obtained, a minimumvalue may be obtained, or the like in order to obtain the physical linkdelay between the two adjacent network nodes. Further, the firstneighboring node sends a plurality of delay measurement packets to thefirst network node. The plurality of delay measurement packets may besent at a same time interval, or be sent randomly, that is, theplurality of delay measurement packets are sent at random-numberintervals in order to perform a plurality of times of measurement on thephysical link delay. This is not limited in the present disclosure.

In this embodiment of the present disclosure, because a residence timeof a packet on a network node is closely related to actual load of thenetwork node, a residence time of a delay measurement packet may be veryshort on a no-load network node but may be relatively long on anearly-full-load network node. Therefore, to more precisely reflect aresidence time of a packet, a residence time of each network node may beobtained by querying a mapping table including a correspondence betweennode load and a residence time. In addition, a node residence time of anetwork node may further be determined by a network topology structure,a link medium, a link length, and a device implementation of the nodeitself.

Further, the mapping table including a correspondence between node loadand a residence time of each network node in a network domain may bepre-established on each network node or the mapping table may beobtained through online measurement. This is not limited in the presentdisclosure. For example, for any network node, the mapping tableincluding a correspondence between load and a residence time of thisnetwork node is as follows: (0%, 0 ms); (10%, 0.01 ms); (20%, 0.05 ms);. . . (50%, 0.5 ms); . . . . When load of the network node is 20%, aresidence time of the network node is 0.05 ms. The network node mayobtain a load status in a current state, that is, the node residencetime of the network node may be obtained by querying the mapping table.Load in the current state may be load at any moment or an average valueof load in a period of time, or may be set as load at a specific moment.This is not limited in the present disclosure.

In this embodiment of the present disclosure, each network node maydirectly send the obtained node residence time of the network node toanother network node, or send the mapping table including acorrespondence between load and a residence time of the network node toanother network node, and send a load status of the network node. Inthis way, the other network node may obtain, according to the loadstatus of the network node, the node residence time of the network nodeby querying the mapping table. This is not limited in the presentdisclosure.

In this embodiment of the present disclosure, each network node in thenetwork domain may obtain a physical link delay between each networknode and a neighboring node and a node residence time of each networknode. Further, for the first network node that is any network node inthe network domain, the first network node may obtain the topologyinformation. The topology information may include the first topologyinformation and the second topology information. The first topologyinformation is obtained by the first network node. The first topologyinformation includes the first physical link delay between the firstnetwork node and the first neighboring node and the node residence timeof the first network node. The first neighboring node is a neighboringnode of the first network node. The second topology information is sentby the second network node and received by the first network node. Thesecond network node is any network node in the network domain except thefirst network node. The second topology information includes the secondphysical link delay between the second network node and the secondneighboring node and the node residence time of the second network node.The second neighboring node is a neighboring node of the second networknode.

Optionally, in an embodiment, for example, as shown in FIG. 1, the node1 separately obtains three physical link delays a physical link delaybetween the node 1 and the node 3, that between the node 1 and the node4, and that between the node 1 and the PE 1. The node 1 further obtainsa node residence time of the node 1. The node 1 may send topologyinformation to its neighboring node 4. The topology information includesthe three physical link delays obtained by the node 1 and the noderesidence time of the node 1. After receiving the topology informationsent by the node 1, the node 4 may forward the topology information suchthat each network node may further receive the topology information ofthe node 1. Simultaneously, the node 4 may further send topologyinformation of the node 4 to another node. The topology information ofthe node 4 may include a physical link delay between the node 4 and eachneighboring node and a node residence time of the node 4. Therefore,each network node in the network domain may obtain the topologyinformation of the node 4. By analogy, each node in the network domainmay obtain topology information of all network nodes in the networkdomain.

In this embodiment of the present disclosure, a network node maytransmit topology information using an extended distributed routingprotocol. For example, the routing protocol may be an existing protocolsuch as OSPF, IS-IS, provided that a new routing capability is extendedand parameters including the foregoing measured physical link delay andnode residence time that are corresponding to each neighboring node canbe carried in order to exchange routing information with another networknode in the network domain.

In step S120, the first network node obtains, according to the topologyinformation, the transmission delay of each path between the ingressnode and the egress node that are in the network domain. Thetransmission delay of each path includes a sum of the physical linkdelay between the two adjacent network nodes on each path and noderesidence times of all network nodes on each path. Further, each networknode in the network domain may obtain the topology information of allthe network nodes in the network domain. Therefore, the transmissiondelay of each path between the ingress node and the egress node that arein the network domain may be calculated by each node in the networkdomain, some nodes in the network domain, any node in the networkdomain, or the ingress node or the egress node in the network domain.This is not limited in the present disclosure.

Optionally, in an embodiment, for example, as shown in FIG. 1, for apath PE1-1-3-6-PE2 between the ingress node and the egress node, atransmission delay of the path is equal to a sum obtained by adding asum of four physical link delays that are respectively between the PE1and the node 1, the node 1 and the node 3, the node 3 and the node 6,and the node 6 and the PE2 and a sum of node residence times of all thefive network nodes, the PE1, the node 1, the node 3, the node 6, and thePE2. Transmission delays of all paths in the network domain aresequentially calculated. For example, as shown in FIG. 1, there aretotally 12 paths between the ingress node PE1 and the egress node PE2,and any network node in the network domain can calculate thetransmission delay of each path.

In step S130, the first network node determines the target transmissionpath between the ingress node and the egress node according to thetransmission delay of each path. Further, the first network node in thenetwork domain may determine, according to the transmission delay ofeach path between the ingress node and the egress node, a transmissionpath meeting the delay requirement as the target transmission path.Optionally, the target transmission path may be one path meeting thedelay requirement or a plurality of paths that meet the delayrequirement for joint transmission. Optionally, a transmission pathbetween the ingress node and the egress node meets a delay requirement.The delay requirement may be that a transmission delay of a low-delayservice packet needs to be less than or equal to a preset value. In thiscase, a path that is in all the paths between the ingress node and theegress node and whose transmission delay is less than or equal to thepreset value may be determined as the target transmission path. Thetarget transmission path is used to transmit a low-delay service packetin a low-delay queue.

Optionally, for each transmission path that is between the ingress nodeand the egress node and that meets the delay requirement, a transmissionpath with a minimum transmission delay may be determined as the targettransmission path. For example, as shown in FIG. 1, if the PE1 is theingress node and the PE2 is the egress node, there are totally 12 pathsbetween the PE1 and the PE2. The transmission delay of each path iscalculated to determine a transmission path with a minimum transmissiondelay as the target transmission path. A low-delay service packet istransmitted using the target transmission path in order to ensure thattransmission of a low-delay service in the network meets the delayrequirement.

Optionally, when at least two transmission paths meeting the delayrequirement exist between the ingress node and the egress node, any oneof the at least two transmission paths may be selected as the targettransmission path.

Optionally, when at least two transmission paths meeting the delayrequirement exist between the ingress node and the egress node, the atleast two transmission paths may all be determined as the targettransmission paths. Each low-delay service packet in a low-delay packetqueue can be transmitted on each target transmission path. For example,as shown in FIG. 1, if the PE1 is the ingress node and the PE2 is theegress node, there are totally 12 paths between the PE1 and the PE2. Thetransmission delay of each path is calculated. It is assumed that thereare totally three transmission paths, which are respectivelyPE1-1-3-6-PE2, PE1-1-4-7-PE2, and PE1-2-4-6-PE2, whose transmissiondelays meet the delay requirement. All the three transmission paths maybe determined as the target transmission paths. All low-delay servicepackets in a low-delay packet queue are transmitted on the three paths,thereby improving transmission reliability of a low-delay service.

Optionally, when at least two transmission paths meeting the delayrequirement exist between the ingress node and the egress node, the atleast two transmission paths may all be determined as the targettransmission paths. A low-delay service packet in a low-delay packetqueue can be transmitted on each target transmission path in a loadsharing manner. For example, as shown in FIG. 1, if the PE1 is theingress node and the PE2 is the egress node, there are totally 12 pathsbetween the PE1 and the PE2. The transmission delay of each path iscalculated. It is assumed that there are totally three transmissionpaths, which are respectively PE1-1-3-6-PE2, PE1-1-4-7-PE2, andPE1-2-4-6-PE2, whose transmission delays meet the delay requirement. Allthe three transmission paths may be determined as the targettransmission paths. Low-delay service packets in a low-delay packetqueue are allocated, according to load in a load sharing manner, to thethree target transmission paths for joint transmission, that is, somelow-delay service packets are separately transmitted on each of thethree target transmission paths. The three target transmission pathsjointly complete transmission of the low-delay service packets. In thisway, a plurality of low-delay paths between the ingress node and theegress node in the network can be fully utilized, thereby improving thetransmission reliability of the low-delay service.

It should be understood that sequence numbers of the foregoing processesdo not mean execution sequences in various embodiments of the presentdisclosure. The execution sequences of the processes should bedetermined according to functions and internal logic of the processes,and should not be construed as any limitation on the implementationprocesses of the embodiments of the present disclosure.

Therefore, according to the method for obtaining a target transmissionpath in this embodiment of the present disclosure, each network node inthe network domain measures the physical link delay between each networknode and a neighboring node, and the node residence time. Each networknode may obtain a physical link delay between other nodes and noderesidence times of the other nodes using topology information in orderto determine the target transmission path that is in the network domainand that meets the delay requirement, and transmit a low-delay servicepacket using the target transmission path. Therefore, this can ensurethat transmission of a low-delay service in the network meets the delayrequirement, and a plurality of low-delay paths between the ingress nodeand the egress node in the network can be fully utilized, therebyimproving transmission reliability of the low-delay service.

The foregoing describes, in detail with reference to FIG. 1 to FIG. 3,the method for obtaining a target transmission path according to theembodiment of the present disclosure. The following describes, withreference to FIG. 4 to FIG. 5, a network node for obtaining a targettransmission path according to an embodiment of the present disclosure.

As shown in FIG. 4, a network node 200 for obtaining a targettransmission path according to an embodiment of the present disclosureis a first network node in a network domain. The network node 200 mayinclude a first obtaining unit 210 configured to obtain topologyinformation of the network domain, where the topology informationincludes a physical link delay between every two network nodes in aplurality of network nodes and a node residence time of each of theplurality of network nodes, a second obtaining unit 220 configured toobtain, according to the topology information, a transmission delay ofeach path between an ingress node and an egress node that are in theplurality of network nodes, where the transmission delay of each pathincludes a sum of physical link delays between all network nodes on eachpath and node residence times of all the network nodes on each path, anda determining unit 230 configured to determine a target transmissionpath according to the transmission delay of each path.

Therefore, according to the network node for obtaining a targettransmission path in this embodiment of the present disclosure, eachnetwork node in the network domain measures a physical link delaybetween each network node and a neighboring node and a node residencetime. Each network node may obtain a physical link delay between othernodes and node residence times of the other nodes using topologyinformation in order to determine a target transmission path that is inthe network domain and that meets a delay requirement, and transmit alow-delay service packet using the target transmission path. Therefore,this can ensure that transmission of a low-delay service in a networkmeets the delay requirement, and a plurality of low-delay paths betweenthe ingress node and the egress node in the network can be fullyutilized, thereby improving transmission reliability of the low-delayservice.

Optionally, the first obtaining unit 210 may further be configured toobtain topology information of all network nodes in the network domain.The topology information of all the network nodes includes a physicallink delay between two adjacent network nodes in the network domain anda node residence time of each network node in the network domain.

Optionally, the topology information includes first topologyinformation, and the first obtaining unit 210 is further configured toobtain a first physical link delay in the first topology information,where the first physical link delay is a link delay between the firstnetwork node and an adjacent first neighboring node, and the firstneighboring node and the first network node belong to the plurality ofnetwork nodes, and obtain a node residence time that is of the firstnetwork node and that is in the first topology information.

Optionally, the topology information includes second topologyinformation, and the first obtaining unit 210 is further configured toreceive the second topology information sent by a second network node inthe plurality of network nodes. The second topology information includesa second physical link delay between the second network node and asecond neighboring node in the plurality of network nodes and a noderesidence time of the second network node, and the second neighboringnode is a neighboring node of the second network node.

Optionally, the first obtaining unit 210 is further configured to obtainload of the first network node, and obtain the node residence time ofthe first network node according to the load and a mapping table. Themapping table includes a correspondence between the load and the noderesidence time that are of the first network node.

Optionally, the first obtaining unit 210 is further configured toreceive a delay measurement packet directly sent by the firstneighboring node, where the delay measurement packet includes a sendingtime stamp of sending the delay measurement packet by the firstneighboring node, and obtain the first physical link delay between thefirst network node and the first neighboring node according to areceiving time stamp of receiving the delay measurement packet and thesending time stamp in the delay measurement packet.

Optionally, the first obtaining unit 210 is further configured toreceive a plurality of delay measurement packets directly sent by thefirst neighboring node, where each of the plurality of delay measurementpackets includes a sending time stamp of sending each delay measurementpacket by the first neighboring node, obtain a plurality of physicallink delays between the first network node and the first neighboringnode according to a receiving time stamp of receiving each delaymeasurement packet and the sending time stamp in each delay measurementpacket, and determine the first physical link delay by collectingstatistics on the plurality of physical link delays.

Optionally, the target transmission path is used to transmit a low-delayservice packet in a low-delay packet queue, and a transmission delay ofthe target transmission path meets a delay requirement of the low-delayservice packet.

Optionally, the determining unit 230 is further configured to determine,as the target transmission path, a path that is in all paths between theingress node and the egress node and that is corresponding to a minimumtransmission delay.

Optionally, the determining unit 230 is further configured to determine,as the target transmission path, one path in a plurality of paths thatare in all paths between the ingress node and the egress node and whosetransmission delays meet the delay requirement.

Optionally, the determining unit 230 is further configured to determine,as the target transmission path, at least two paths in a plurality ofpaths that are in all paths between the ingress node and the egress nodeand whose transmission delays meet the delay requirement of thelow-delay service packet. Each of the at least two paths separatelytransmits each low-delay service packet in the low-delay packet queue.

Optionally, the determining unit 230 is further configured to determine,as the target transmission path, at least two paths in a plurality ofpaths that are in all paths between the ingress node and the egress nodeand whose transmission delays meet the delay requirement of thelow-delay service packet. The at least two paths transmit the low-delayservice packet in the low-delay packet queue in a load sharing manner.

Optionally, the first network node is the ingress node or the egressnode.

Optionally, the second network node is the ingress node or the egressnode.

It should be understood that the network node 200 herein is implementedin a form of a functional unit. The term “unit” may be anapplication-specific integrated circuit (ASIC), an electronic circuit, aprocessor (such as a shared processor, a dedicated processor, or a groupprocessor) configured to execute one or more software or firmwareprograms, a memory, a combined logic circuit, and/or another appropriatecomponent that supports the described functions. In an optional example,a person skilled in the art may understand that the network node 200 maybe the first network node in the foregoing embodiment, and the foregoingand other operations and/or functions of the units in the network node200 are respectively used to implement the corresponding procedures ofthe method in FIG. 2. For brevity, details are not described herein.

Therefore, according to the network node for obtaining a targettransmission path in this embodiment of the present disclosure, eachnetwork node in the network domain measures a physical link delaybetween each network node and a neighboring node and a node residencetime. Each network node may obtain a physical link delay between othernodes and node residence times of the other nodes using topologyinformation in order to determine a target transmission path that is inthe network domain and that meets a delay requirement, and transmits alow-delay service packet using the target transmission path. Therefore,this can ensure that transmission of a low-delay service in a networkmeets the delay requirement, and a plurality of low-delay paths betweenthe ingress node and the egress node in the network can be fullyutilized, thereby improving transmission reliability of the low-delayservice.

As shown in FIG. 5, an embodiment of the present disclosure furtherprovides a network node 300 for obtaining a target transmission path.The network node is a first network node in a network domain including aplurality of network nodes. The network node 300 includes a processor310, a memory 320, and a bus system 330. The processor 310 and thememory 320 are connected to each other using the bus system 330. Thememory 320 is configured to store an instruction. The processor 310 isconfigured to execute the instruction stored by the memory 320.Optionally, the network node 300 shown in FIG. 5 may further include acommunications interface (not shown in FIG. 5) configured forcommunication with the outside. The processor 310 may communicate withan external device using the communications interface.

The memory 320 stores program code, and the processor 310 may invoke theprogram code stored in the memory 320 to perform the followingoperations of obtaining topology information of the network domain,where the topology information includes a physical link delay betweenevery two network nodes in the plurality of network nodes and a noderesidence time of each of the plurality of network nodes, obtaining,according to the topology information, a transmission delay of each pathbetween an ingress node and an egress node that are in the plurality ofnetwork nodes, where the transmission delay of each path includes a sumof physical link delays between all network nodes on each path and noderesidence times of all the network nodes on each path, and determining atarget transmission path according to the transmission delay of eachpath.

Therefore, according to the network node for obtaining a targettransmission path in this embodiment of the present disclosure, eachnetwork node in the network domain measures a physical link delaybetween each network node and a neighboring node and a node residencetime. Each network node may obtain a physical link delay between othernodes and node residence times of the other nodes using topologyinformation in order to determine a target transmission path that is inthe network domain and that meets a delay requirement, and transmit alow-delay service packet using the target transmission path. Therefore,this can ensure that transmission of a low-delay service in a networkmeets the delay requirement, and a plurality of low-delay paths betweenthe ingress node and the egress node in the network can be fullyutilized, thereby improving transmission reliability of the low-delayservice.

It should be understood that in this embodiment of the presentdisclosure, the processor 310 may be a central processing unit (CPU), orthe processor 310 may be another general-purpose processor, a digitalsignal processor (DSP), an ASIC, a field programmable gate array (FPGA),or another programmable logic device, discrete gate or transistor logicdevice, discrete hardware component, or the like. The general-purposeprocessor may be a microprocessor, or the processor may be any normalprocessor, or the like.

The memory 320 may include a read-only memory (ROM) and a random accessmemory (RAM), and provides an instruction and data for the processor310. A part of the memory 320 may further include a nonvolatile RAM. Forexample, the memory 320 may further store information about a devicetype.

In addition to a data bus, the bus system 330 may further include apower bus, a control bus, a status signal bus, and the like. However,for clarity of description, various buses are marked as the bus system330 in FIG. 5.

In an implementation process, the steps in the foregoing method may becompleted using an integrated logic circuit of hardware in the processor310 or an instruction in a form of software. The steps of the methoddisclosed with reference to the embodiments of the present disclosuremay be directly performed by a hardware processor, or may be performedusing a combination of hardware in the processor and a software module.A software module may be located in a mature storage medium in the art,such as a RAM, a flash memory, a ROM, a programmable ROM (PROM), anelectrically erasable PROM, or a register. The storage medium is locatedin the memory 320. The processor 310 reads information in the memory320, and completes the steps of the foregoing method in combination withhardware of the processor 310. To avoid repetition, details are notdescribed herein again.

Optionally, in an embodiment, the processor 310 is further configured toobtain topology information of all network nodes in the network domain.The topology information of all the network nodes includes a physicallink delay between two adjacent network nodes in the network domain anda node residence time of each network node in the network domain.

Optionally, in an embodiment, the topology information includes firsttopology information, and the processor 310 is further configured toobtain a first physical link delay in the first topology information,where the first physical link delay is a link delay between the firstnetwork node and an adjacent first neighboring node, and the firstneighboring node and the first network node belong to the plurality ofnetwork nodes, and obtain a node residence time that is of the firstnetwork node and that is in the first topology information.

Optionally, in an embodiment, the topology information includes secondtopology information, and the processor 310 is further configured toreceive the second topology information sent by a second network node inthe plurality of network nodes. The second topology information includesa second physical link delay between the second network node and asecond neighboring node in the plurality of network nodes and a noderesidence time of the second network node, and the second neighboringnode is a neighboring node of the second network node.

Optionally, in an embodiment, the processor 310 is further configured toobtain load of the first network node, and obtain the node residencetime of the first network node according to the load and a mappingtable. The mapping table includes a correspondence between the load andthe node residence time that are of the first network node.

Optionally, in an embodiment, the processor 310 is further configured toreceive a delay measurement packet directly sent by the firstneighboring node, where the delay measurement packet includes a sendingtime stamp of sending the delay measurement packet by the firstneighboring node, and obtain the first physical link delay between thefirst network node and the first neighboring node according to areceiving time stamp of receiving the delay measurement packet and thesending time stamp in the delay measurement packet.

Optionally, in an embodiment, the processor 310 is further configured toreceive a plurality of delay measurement packets directly sent by thefirst neighboring node, where each of the plurality of delay measurementpackets includes a sending time stamp of sending each delay measurementpacket by the first neighboring node, obtain a plurality of physicallink delays between the first network node and the first neighboringnode according to a receiving time stamp of receiving each delaymeasurement packet and the sending time stamp in each delay measurementpacket, and determine the first physical link delay by collectingstatistics on the plurality of physical link delays.

Optionally, in an embodiment, the target transmission path is used totransmit a low-delay service packet in a low-delay packet queue, and atransmission delay of the target transmission path meets a delayrequirement of the low-delay service packet.

Optionally, in an embodiment, the processor 310 is further configured todetermine, as the target transmission path, a path that is in all pathsbetween the ingress node and the egress node and that is correspondingto a minimum transmission delay.

Optionally, in an embodiment, the processor 310 is further configured todetermine, as the target transmission path, one of a plurality of pathsthat are in all paths between the ingress node and the egress node andwhose transmission delays meet the delay requirement.

Optionally, in an embodiment, the processor 310 is further configured todetermine, as the target transmission path, at least two paths in aplurality of paths that are in all paths between the ingress node andthe egress node and whose transmission delays meet the delay requirementof the low-delay service packet. Each of the at least two pathsseparately transmits each low-delay service packet in the low-delaypacket queue.

Optionally, in an embodiment, the processor 310 is further configured todetermine, as the target transmission path, at least two paths in aplurality of paths that are in all paths between the ingress node andthe egress node and whose transmission delays meet the delay requirementof the low-delay service packet. The at least two paths transmit thelow-delay service packet in the low-delay packet queue in a load sharingmanner.

Optionally, in an embodiment, the first network node is the ingress nodeor the egress node.

Optionally, in an embodiment, if the first network node is the ingressnode, the second network node is the egress node, and if the firstnetwork node is the egress node, the second network node is the ingressnode.

It should be understood that the network node 300 for obtaining a targettransmission path according to this embodiment of the present disclosuremay be corresponding to the network node 200 for obtaining a targettransmission path in the embodiment of the present disclosure, and maybe corresponding to a corresponding execution body that executes themethod 100 according to the embodiment of the present disclosure. Inaddition, the foregoing and other operations and/or functions of themodules of the network node 300 for obtaining a target transmission pathare respectively used to implement corresponding procedures of themethod in FIG. 2. For brevity, details are not described herein again.

Therefore, according to the network node for obtaining a targettransmission path in this embodiment of the present disclosure, eachnetwork node in the network domain measures a physical link delaybetween each network node and a neighboring node and a node residencetime. Each network node may obtain a physical link delay between othernodes and node residence times of the other nodes using topologyinformation in order to determine a target transmission path that is inthe network domain and that meets a delay requirement, and transmit alow-delay service packet using the target transmission path. Therefore,this can ensure that transmission of a low-delay service in a networkmeets the delay requirement, and a plurality of low-delay paths betweenthe ingress node and the egress node in the network can be fullyutilized, thereby improving transmission reliability of the low-delayservice.

A person of ordinary skill in the art may be aware that, in combinationwith the examples described in the embodiments disclosed in thisspecification, units and algorithm steps may be implemented byelectronic hardware or a combination of computer software and electronichardware. Whether the functions are performed by hardware or softwaredepends on particular applications and design constraint conditions ofthe technical solutions. A person skilled in the art may use differentmethods to implement the described functions for each particularapplication, but it should not be considered that the implementationgoes beyond the scope of the present disclosure.

It may be clearly understood by a person skilled in the art that, forthe purpose of convenient and brief description, for a detailed workingprocess of the foregoing system, apparatus, and unit, reference may bemade to a corresponding process in the foregoing method embodiments, anddetails are not described herein again.

In the several embodiments provided in this application, it should beunderstood that the disclosed system, apparatus, and method may beimplemented in other manners. For example, the described apparatusembodiment is merely an example. For example, the unit division ismerely logical function division and may be other division in actualimplementation. For example, a plurality of units or components may becombined or integrated into another system, or some features may beignored or not performed. In addition, the displayed or discussed mutualcouplings or direct couplings or communication connections may beimplemented using some interfaces. The indirect couplings orcommunication connections between the apparatuses or units may beimplemented in electronic, mechanical, or other forms.

The units described as separate parts may or may not be physicallyseparate, and parts displayed as units may or may not be physical units,may be located in one position, or may be distributed on a plurality ofnetwork units. Some or all of the units may be selected according toactual requirements to achieve the objectives of the solutions of theembodiments.

In addition, functional units in the embodiments of the presentdisclosure may be integrated into one processing unit, or each of theunits may exist alone physically, or two or more units are integratedinto one unit.

When the functions are implemented in the form of a software functionalunit and sold or used as an independent product, the functions may bestored in a computer-readable storage medium. Based on such anunderstanding, the technical solutions of the present disclosureessentially, or the part contributing to other approaches, or some ofthe technical solutions may be implemented in a form of a softwareproduct. The software product is stored in a storage medium, andincludes several instructions for instructing a computer device (whichmay be a personal computer, a server, or a network device) to performall or some of the steps of the methods described in the embodiments ofthe present disclosure. The foregoing storage medium includes any mediumthat can store program code, such as a universal serial bus (USB) flashdrive, a removable hard disk, a ROM, a RAM, a magnetic disk, or anoptical disc.

Finally, it should be noted that the foregoing embodiments are merelyused as examples for describing the technical solutions of the presentdisclosure other than to limit the present disclosure. Although thepresent disclosure and benefits of the present disclosure are describedin detail with reference to the foregoing embodiments, a person ofordinary skill in the art should understand that the person may stillmake modifications to the technical solutions described in the foregoingembodiments or make equivalent replacements to some technical featuresthereof, without departing from the scope of the claims of the presentdisclosure.

What is claimed is:
 1. A method for obtaining a target transmissionpath, applied to a network domain, comprising: obtaining, by a firstnetwork node in the network domain, topology information of a pluralityof network nodes comprised by each path between an ingress node and anegress node in the network domain, the topology information comprising aphysical link delay between two adjacent network nodes in the networknodes and a node residence time of each of the network nodes; obtaining,by the first network node, a transmission delay of each path between theingress node and the egress node according to the topology information,the transmission delay of each path comprising a sum of the physicallink delay between the two adjacent network nodes on each path and noderesidence times of the network nodes on each path; determining, by thefirst network node, the target transmission path between the ingressnode and the egress node according to the transmission delay of eachpath; and transmitting, by the first network node, a low-delay servicepacket using the target transmission path.
 2. The method of claim 1,wherein the topology information further comprises first topologyinformation, and obtaining the topology information of the network nodescomprising: obtaining, by the first network node, a first physical linkdelay in the first topology information, the first physical link delaycomprising a link delay between the first network node and an adjacentfirst neighboring node; and obtaining, by the first network node, a noderesidence time of the first network node in the first topologyinformation.
 3. The method of claim 1, wherein the topology informationfurther comprises second topology information, obtaining the topologyinformation of the network nodes comprising receiving, by the firstnetwork node, the second topology information from a second network nodein the network nodes, the second topology information comprising asecond physical link delay between the second network node and a secondneighboring node in the network nodes and a node residence time of thesecond network node, and the second neighboring node comprising aneighboring node of the second network node.
 4. The method of claim 2,wherein obtaining the node residence time of the first network node inthe first topology information comprises: obtaining, by the firstnetwork node, load of the first network node; and obtaining, by thefirst network node, the node residence time of the first network nodeaccording to the load and a mapping table, the mapping table comprisinga correspondence between the load and the node residence time of thefirst network node.
 5. The method of claim 2, wherein obtaining thefirst physical link delay in the first topology information comprises:receiving, by the first network node, a delay measurement packetdirectly from the first neighboring node, the delay measurement packetcomprising a sending time stamp of sending the delay measurement packetby the first neighboring node; and obtaining, by the first network node,the first physical link delay according to a receiving time stamp ofreceiving the delay measurement packet and the sending time stamp in thedelay measurement packet.
 6. The method of claim 2, wherein obtainingthe first physical link delay in the first topology informationcomprises: receiving, by the first network node, a plurality of delaymeasurement packets directly from the first neighboring node, each ofthe delay measurement packets comprising a sending time stamp of sendingeach delay measurement packet by the first neighboring node; obtaining,by the first network node, a plurality of physical link delays betweenthe first network node and the first neighboring node according to areceiving time stamp of receiving each delay measurement packet and thesending time stamp in each delay measurement packet; and determining, bythe first network node, the first physical link delay by collectingstatistics on the physical link delays.
 7. The method of claim 1,wherein the low-delay service packet is transmitted in a low-delaypacket queue, and a transmission delay of the target transmission pathmeeting a delay requirement of the low-delay service packet.
 8. Themethod of claim 7, wherein determining the target transmission pathbetween the ingress node and the egress node comprises determining, bythe first network node as the target transmission path, at least twopaths in a plurality of paths in all paths between the ingress node andthe egress node whose transmission delays meet the delay requirement ofthe low-delay service packet, and the at least two paths transmittingthe low-delay service packet in the low-delay packet queue in a loadsharing manner.
 9. A first network node in a network domain forobtaining a target transmission path, comprising: a processor; and anon-transitory computer-readable storage medium coupled to the processorand storing programming instructions for execution by the processor, theprogramming instructions causing the processor to be configured to:obtain topology information of a plurality of network nodes comprised byeach path between an ingress node and an egress node in the networkdomain, the topology information comprising a physical link delaybetween two adjacent network nodes in the network nodes and a noderesidence time of each of the network nodes; obtain a transmission delayof each path between the ingress node and the egress node according tothe topology information, the transmission delay of each path comprisinga sum of the physical link delay between the two adjacent network nodeson each path and node residence times of the network nodes on each path;determine the target transmission path between the ingress node and theegress node according to the transmission delay of each path; andtransmit a low-delay service packet using the target transmission path.10. The network node of claim 9, wherein the topology informationfurther comprises first topology information, and the programminginstructions further causing the processor to be configured to: obtain afirst physical link delay in the first topology information, the firstphysical link delay comprising a link delay between the first networknode and an adjacent first neighboring node, and the first neighboringnode and the first network node belonging to the network nodes; andobtain a node residence time of the first network node in the firsttopology information.
 11. The network node of claim 9, wherein thetopology information further comprises second topology information, theprogramming instructions further causing the processor to be configuredto receive the second topology information from a second network node inthe network nodes, the second topology information comprising a secondphysical link delay between the second network node and a secondneighboring node in the network nodes and a node residence time of thesecond network node, and the second neighboring node comprising aneighboring node of the second network node.
 12. The network node ofclaim 10, wherein the programming instructions further cause theprocessor to be configured to: obtain load of the first network node;and obtain the node residence time of the first network node accordingto the load and a mapping table, the mapping table comprising acorrespondence between the load and the node residence time of the firstnetwork node.
 13. The network node of claim 10, wherein the programminginstructions further cause the processor to be configured to: receive adelay measurement packet directly from the first neighboring node, thedelay measurement packet comprising a sending time stamp of sending thedelay measurement packet by the first neighboring node; and obtain thefirst physical link delay according to a receiving time stamp ofreceiving the delay measurement packet and the sending time stamp in thedelay measurement packet.
 14. The network node of claim 10, wherein theprogramming instructions further cause the processor to be configuredto: receive a plurality of delay measurement packets directly from thefirst neighboring node, each of the delay measurement packets comprisinga sending time stamp of sending each delay measurement packet by thefirst neighboring node; obtain a plurality of physical link delaysbetween the first network node and the first neighboring node accordingto a receiving time stamp of receiving each delay measurement packet andthe sending time stamp in each delay measurement packet; and determinethe first physical link delay by collecting statistics on the physicallink delays.
 15. The network node of claim 9, wherein the low-delayservice packet is transmitted in a low-delay packet queue, and atransmission delay of the target transmission path meeting a delayrequirement of the low-delay service packet.
 16. The network node ofclaim 15, wherein the programming instructions further cause theprocessor to be configured to determine, as the target transmissionpath, at least two paths in a plurality of paths in all paths betweenthe ingress node and the egress node whose transmission delays meet thedelay requirement of the low-delay service packet, and the at least twopaths transmitting the low-delay service packet in the low-delay packetqueue in a load sharing manner.